Idiosyncratic paragraphs Text-only paragraphs differ from one another only in their words. All the words are typographically the same – typeface, spacings, line-lengths piled up into long deep columns. Systematic regularity of text paragraphs is universally inconvenient for readers, who are unable to find and read once against a specific string of words in previously-read paragraphs. All readers have encountered this problem in essays, articles, novels, news reports. Idiosyncratic paragraphs assist memory and retrieval by readers, by uniquely activating the relevant neural substrates for retaining visual memories. Nearly every paragraph in this book is deliberately unique. Edward Tufte, Seeing With Fresh Eyes variation
Materials and how to employ them Forming a paper clip presents a common dilemma encountered by engineers and inventors: the very properties of the material that make it possible to be shaped into a useful object also limit its use. If one were to try and make a paper clip out of wire that stayed bent too easily, it would have little spring and not hold papers very tightly. On the other hand, if one were to use wire that did not stay bent, then the clip could not even be formed. Thus, understanding the fundamental behavior of materials and how to employ them to advantage is often a principle reason that something as seemingly simple as a paper clip cannot be developed sooner than it is. Henry Petroski, The Evolution of Useful Things Ideas behind their time material